Feel like Outlook is a bit too keen to tell you every time you get new mail? Trying to be more disciplined in when you check email? The Outlook Team Blog has a handy guide to how to switch off the various notifications within Outlook. This isn't a particularly obvious process, but the post also promises improvements in the future:
They're a bit hard to find in our Options dialogs, and that's something we hope to address in a future release of Outlook.
Making Outlook a little quieter [Outlook Team Blog]